Enhanced oxytetracycline photocatalytic degradation via ferroelectric polarization-engineered TiO2/BTO-P/GQDs heterostructure: Synergistic rapid charge extraction and comprehensive reactive site optimization

Titanium dioxide (TiO 2 ) has been extensively utilized owing to its outstanding physicochemical properties in the field of photocatalytic degradation. However, its efficiency is fundamentally limited by poor charge carrier mobility and severe recombination. These defects critically impair both charge utilization and reactive oxygen species generation. Herein, we in-situ hydrothermally grow ferroelectric barium titanate (BTO) layers on vertically aligned TiO 2 nanorod arrays (NRs), polarize the sample via an external electric field, and load graphene quantum dots (GQDs) through controlled impregnation, successfully constructing a TiO 2 /BTO-Polarized/GQDs (TiO 2 /BTO-P/GQDs) heterostructure. An external electric field induces a stable depolarization field in the BTO layer, creating a persistent interfacial driving force that enhances charge extraction from TiO 2 while suppressing bulk and surface electron-hole recombination. The BTO layer further acts as an electron transfer highway, efficiently channeling photogenerated electrons to GQDs. The π-conjugated system of GQDs serves as both an electron accumulation platform and a chemically active surface, facilitating pollutant adsorption and activation, thereby synergistically accelerating degradation kinetics through combined electron storage and catalytic effects. TiO 2 /BTO-P/GQDs demonstrated a 2.06-fold higher (OTC) degradation efficiency (82.5%) compared to unmodified TiO 2 (40%) within 90 min. This study provides novel insights into ferroelectric polarization-enhanced photocatalytic degradation efficiency. Implication This work presents a highly efficient, stable, and recoverable photocatalyst (TiO 2 /BTO-P/GQDs) for degrading persistent antibiotic pollutants like oxytetracycline in water. By enabling effective solar-driven remediation of agricultural wastewater, it offers a promising strategy to mitigate antibiotic contamination, protect aquatic ecosystems, and reduce risks to microbial communities and human health associated with residual antibiotics in the environment.